Chapter II

Tinker wasn’t a fool, for all that he liked to play games. The two of them went back to work. Around them, as they labored at the difficult task of rearranging the circuits in accordance with Siria Cottrell’s wiring diagrams, fresh from the Home Office, the robots moved mechanically about their affairs. They were making isotopes, and it was no concern of their electronic brains if human visitors decided to change the way in which they made them.

In vast, open-walled buildings on the far side of the asteroid, atomic nuclei were reacting. The process was slow, by atomic standards, but it was steady, and it went on day and night, week and month and year without end. The cascade refiners turned out a constant stream of ultra-pure, long-life isotope ingots, and the unmanned space ships came in a steady stream to the little five-mile chunks of rock, arriving empty, and departing with full loads.

It was a scene of never-ceasing activity, but soundless--without air--and the busiest components of the landscape, the reactors and refiners, remained out of sight. Equally invisible was the radiation range, except for a comparatively tiny seepage.

Of course, the seepage didn’t bother the robots, for their special sensory receptors--the instruments which Tinker called the “heads”--were in dummy sockets and not plugged in at the apex. Their usual sense organs, located in the torso itself, had what the manuals described as “_Class I adjacent-band interference rejection_.” In other words, they weren’t very sensitive.

But the heads, designed to pick up minute sparks from defective equipment, and used only for diagnosing breakdowns, were so abnormally sensitive that they were eventually certain to pick up constant static signals from the reactors.

That meant, of course, that they couldn’t be worn all the time. The robot “neural” system was almost inflexible but constant faint signals would derange it, confuse the robot reflexes and eventually lead to a condition that the manuals defined as “_crystalline neurosis_.”

Crystalline neurosis indeed! But Tinker knew what it meant in practice, at least. It meant that something had gone wrong that the robots themselves couldn’t repair, and that was why he and Drake were handily next door, sweating out their contract time in a well-insulated space house equipped with air and water purifiers, on Asteroid B.

The radio crackled in Tinker’s ear. “What’s the matter with that one?” the girl demanded.

Tinker looked up. The girl was standing over him, working on an overhead grouping of the circuits--except that she wasn’t actually working. She was staring out at the scene beyond the shed, where one of the robots was down on the rock, kicking feebly.

Tinker said, “Our excellent friend is busted. A part wore out, I suppose. We may as well watch, and see how they fix it.”

Scarcely a minute later two more robots appeared and moved purposefully toward the fallen one. As they advanced the two new arrivals tugged their heads free from under their arms, and shifted them to their broad metal “shoulders.” A slight twist, and they were no longer headless.

The girl said humbly, “Tinker, explain it to me, please? I know all about the manuals--I helped write parts of them. But it all looks so different out here in the field.”

Tinker said, “Glad to oblige. You’re familiar with central control--the computer that programs all the robots? Well, when one of them breaks down, the nearest adjacent unit gets a distress signal. Instantly our dutiful friends stick their heads on--just as those two did. And--well, look.”

The two robots had suddenly become mechanics. With incredible, expert swiftness they had their fallen companion in sections, right there on the rock. The tiny individual parts were passed before the region where their eyes would have been--if the “head” had possessed eyes--in a complex gesture which the girl was sure involved some sort of testing.

It took hardly a minute before one of the newcomers located the faulty part--a worn out thermocouple. The second quickly detached his head again, and somehow managed to open a section of it. Out of the cavity thus exposed came a duplicate thermocouple to replace the old one. In another minute all three of the robots had their heads off and stored once more. The damaged one, looking assured, immediately sprang to his feet, and resumed his interrupted task.

“Clever, isn’t it?” Tinker said. “Tool chest, stockroom, testing instruments--all in one.”

The girl said doubtfully, “But why do they have their own individual heads? I should think just a couple scattered around the asteroid would suffice.”

“Why does every Ford have a jack in the luggage compartment?” Tinker asked, “Isn’t it obvious? They’re built to be self-sufficient. And they just about have to be, Siria. This is a very small asteroid. Quite frequently Drake and I kick ourselves uncomfortably far off the surface, to where the artificial gravity in our suits won’t bring us back. The robots don’t even have artificial gravity, and if anything went wrong with _them_ out in space, they’d have to repair themselves.”

“I see what you mean,” the girl said. “But are you seriously suggesting that those heads can handle anything that goes wrong?”

“No, of course not,” Tinker said. “Not by themselves, at any rate. They’re just testing equipment and so on. The brains--the repair patterns, if you don’t like your robot men so anthropomorphic--are in the central control system. Do you know,” he went on quite irrelevantly, “that you have beautiful eyes?”

She laughed after a moment. “It may have been three months since you saw a woman. But you haven’t forgotten the meaning of a smooth line. Let’s get back to work.”

A moment later a flicker in the corner of her eye caught the girl’s attention, and she glanced up, startled. Overhead a large black shape was blotting out a chunk of the skyful of stars.

Tinker laughed. “B,” he said simply.

* * * * *

She nodded, staring. It had been a growing mountain, off on the horizon far to her left, a cold asteroid Paricutin, getting taller by the moment. Now it had separated and was floating free. Even as they watched, it climbed higher in the sky, looking like some plunging hell-bomb above a city pin-pointed for atomic disaster on a tragically conclusive scale.

“It isn’t falling,” Tinker reassured her. “It’s just home sweet home--Asteroid Y-335 B.”

“I know it isn’t falling,” she breathed, drawing closer to him. “It’s just that I can’t get used to its being up there at all.”

Tinker sighed. “I have to get used to it because I’d be homeless if it disappeared. Atmosphere artificial, gravity equally plush-velvet. Time of revolution for the binary pair, seventy-five minutes. Population, two--John Tinker, probably lunatic adventurer, and George Drake, possibly dangerously sane rat.”

She glanced at him thoughtfully. “It’s easy to see that you don’t like Drake.”

“You haven’t met Drake,” he explained. “Anyway, it’s not as bad as it might be. There are, I’ll concede, certain physical comforts. The air is kept fresh, and the food is extremely tasty. The drinks taste good--even though they’re non-intoxicating. There is continual radio contact with women on Earth--also non-intoxicating. That’s why, Siria,” he went on earnestly, “I have been urging you to join our little band. _You_ are intoxicating. Will you--”

“Tinker,” she said with reproachful insistence, “will you please keep your mind on business? Will you please--what’s that?”

The B asteroid was still hovering high in the sky but now a tiny black dot was moving out from it, precisely as the planetoid itself had separated from the horizon. They watched it wordlessly for a moment. They could see that it was expanding slowly, changing its shape as it grew. It shrank, and lengthened, dwindled, and swelled, but always its longest aspect was greater than it had been a moment before.

“Drake,” said Tinker proudly, “is a rank amateur.”

“An amateur?”

“At the jump,” Tinker explained. “We have jet-assists to get us from one asteroid to another if we need them. But if we aren’t in a hurry we jump. It’s just as safe, and far more comfortable.”

“But suppose you miss?”

“We never miss,” Tinker said with quiet dignity. But honesty made him add: “Anyway, it’s perfectly safe. We have to cut the artificial gravity in our bootsoles to jump--and if it looks as if we’re drifting off course we just switch it on again. But Drake’s a clumsy amateur. Look at the way he spins! Four or five turns a minute, easy.”

“And you?”

“One turn a minute, maximum.” He made a regal gesture. “Don’t applaud, please. Well--he won’t be here for twenty minutes yet. We might as well get back to work.”